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General Considerations

Neurofibromatosis is a multisystem disorder with a prevalence of 1:3000. Fifty percent of cases are due to new mutations in the NF1 gene, which is located on chromosome 17q11.2 encoding neurofibromin. Forty percent of patients develop medical complications over their lifetime. Two or more positive criteria are diagnostic; others may appear over time. Children with six or more café au lait spots and no other positive criteria should be followed; 95% develop neurofibromatosis type 1.

Clinical Findings

Symptoms and Signs

The most common presenting symptoms are cognitive or psychomotor problems; 40% have learning disabilities, and 8% have intellectual disability. The history should focus on lumps or masses causing disfigurement, functional problems, or pain. Café au lait spots are seen in most affected children by age 1 year. The typical skin lesion is 10–30 mm, ovoid, and smooth-bordered. Discrete well demarcated neurofibromas or lipomas can occur at any age. Plexiform neurofibromas are diffuse and can invade normal tissue. They are congenital and are frequently detected during periods of rapid growth. If the face or a limb is involved, there may be associated hypertrophy or overgrowth.

Clinicians should evaluate head circumference, blood pressure, vision, hearing, spine for scoliosis, and limbs for pseudarthroses. Strabismus or amblyopia dictates a search for optic glioma, a common tumor in neurofibromatosis. The eye examination should include a check for proptosis and iris Lisch nodules. The optic disk should be examined for atrophy or papilledema. Any progressive or new neurologic deficit calls for studies to rule out tumor of the spinal cord or CNS. Short stature and precocious puberty are occasional findings.